Melt the lard in a large, heavy casserole or Dutch oven over moderately high heat.
Add the onions and cook until softened, about 5 minutes, stirring often.
Add the chicken and tomatoes, cover, and cook for 10 minutes.
Stir in the paprika, chicken stock, salt.
Bring to a simmer, then reduce the heat to low, cover again, and cook for 2 minutes.
Remove the lid, increase the heat to moderately high, and let the liquid evaporate.
Brown the chicken in the residual fat, but do not let it burn.
Remove the chicken pieces to a platter and keep warm.
Reduce the heat to moderately How and add the sour cream, flour, and cold water to the Dutch oven; stir until smooth.
Add the green pepper, replace the chicken, and season with salt to taste.
Reduce the heat to low, cover again, and cook for 5 to 10 more minutes.
Stir in the cream just before serving.
To prepare the dumplings, combine the egg, lard, water, and salt in a large mixing bowl.
Mix in the flour just enough to give the dough an even texture.
Set aside and let rest for 10 minutes.
Bring the chicken stock to a boil in a medium saucepan.
Drop the dumplings by large spoorifuls into the stock.
Reduce the heat to moderate, cover, and cook until firm, about 15 minutes.
Lift the dumplings out with a slotted spoon and serve with the chicken.